Makoto, Nishi, and Ozuro were paid a total of $780 for waxing the floors at their school. Each was paid in proportion to the number of hours he or she worked. If Makoto worked 15 hours, Nishi worked 20 hours, and Ozuro worked 30 hours, how much was Makoto paid?

(A) $52

(B) $117

(C) $130

(D) $180

(E) $234

This is a relatively simple work-rate problem. I’ll use the standard W = RT table. The work is represented by the total amount earned. Using that and the total time we can find the hourly rate (which is the same for all three students).

\($780 = {R}\times{65}\)

So, the hourly rate is

\(\frac{780}{65} = \frac{{78}\times{10}}{{13}\times{5}} = \frac{{13}\times{6}\times{5}\times{2}}{{13}\times{5}}\)

Cancelling the 13, and the 5, we end up with $12/hour. Makoto worked 15 hours, so he or she earned $12(15) = $180.

**The correct answer is D.**